Zero additional maintenance stormwater biofilters: from laboratory testing to field implementation

Overview & Synopsis

Stormwater biofilters are one of the most widely used nature-based solutions for urban water management. In the last 20 years, biofilters have been extensively studied for their pollutant removal performance, however, their application in the field is limited by high maintenance requirements. In this work, we propose the concept of Zero Additional Maintenance (ZAM) biofilters. A three-stage research program was conducted to i) examine filter media configurations that could protect against surface clogging, ii) test the pollutant removal performance of a variety of lawn grasses, iii) validate the laboratory findings through field monitoring. The results showed that a protective filter media layer delayed the onset of clogging. Five lawn grasses were found to effectively reduce nitrogen concentrations and meet other local pollution reduction requirements. Monitoring of three field-scale ZAM biofilters confirmed their high nutrient and heavy metal removal performance. Overall, the findings of these three studies confirm the potential for well-designed ZAM biofilters to achieve stormwater management requirements with no additional maintenance compared to standard street landscaping.